Intelligence, inspection time and cognitive strategies

The use of apparent motion cues to guide discriminations on the inspection time (IT) task has been taken to imply the vulnerability of IT to strategic processes by higher IQ subjects, and the questionable generality of the IT/IQ correlation. The current study examined verbal and non-verbal intelligence, personality and IT in 74 young adults, using light-emitting diodes to present IT, obtaining perceptual self-reports during IT itself. Forty-three (58 per cent) subjects in the sample reported using motion cues to guide IT discriminations; these subjects had faster ITs than individuals who did not use motion cues (t = 2.97, p < .005; effect size = .73). Cue users did not have higher verbal or non-verbal IQ than non-users. Although cue users were lower in neuroticism than non-cue users, this did not account for their faster ITs. Slower IT correlated with lower scores on a measure of non-verbal intelligence (r = -0.41, p < .001); the size of this correlation remained similar when the sample was divided into groups reporting the use of motion cues or not. Thus, despite motion cues enhancing performance on an IT task, the perception of these cues neither causes, nor reduces, the correlation between IT and IQ.